A continuing concern of Civil and Military Aviation Authorities, as well as certain Military Group Transportation Authorities, is to ensure that the operators of air planes, ships, and certain vehicles, in the event of emergencies where substantial visual impairment is caused by smoke or other airborne particulate matter in their confined environments, will have sufficient visibility of vital instruments and the external environment, in order to safely land an aircraft or continue to drive a tank or personnel carrier.
To counteract the adverse lacrymatory effects of smoke and toxic fumes pilots, for instance, are provided with goggles and, for respiratory protection, 100% oxygen is also available. This has been the case for approximately the last four decades. In addition, in order to try to provide visual assurance for the pilot to view instruments and be able to see outside the aircraft through the windshield (and for health and comfort reasons, also) fresh air ventilation rates in the cockpits of aircraft (civil transport carriers) have since the early 1950's been on the order of a minimum of 60 cubic feet per person per minute. On the most recently certified aircraft types presently in operation, the fresh air ventilation rates have been increased to approximately 250 cubic feet per person per minute in order to cope with the additional heat loads from electronic equipment and as what really amounts to only a token effort to aid in smoke evacuation during an emergency.
In spite of the long standing problems associated with inflight smoke and fire emergencies (according to FAA records there are more than 600 occurrences annually in this country alone . . . for a fleet of approximately 3,000 aircraft) the present procedures of evacuating and/or diluting the smoke are totally inadequate. This fact is best evidenced by the certification procedure applied by manufacturers and the FAA whereby only a finite amount of smoke is inserted in the cockpit and then shown to be evacuated, as opposed to a constant source of smoke, which would reflect a real life scenario. Even more important is the simple fact that tragedies with substantial loss of life are still occurring on a regular basis in situations where the only substantive cause for the tragedies is the loss of visibility of the instruments and/or external visibility from the aircraft.
A need therefore exists for the provision of pilot visibility of instruments, and visibility through the windshield, no matter how much and how dense the smoke may be in the cockpit.
There are a number of patented prior art devices which, in addition to providing a transparent protective enclosure for the head or face of a person in a hostile environment, are otherwise limited in purpose to only supplying the person with life supporting fresh air or oxygen. Examples of these patented devices are shown in U.S. Pat. Nos. 2,032,101 to Sullivan; 4,221,216 to Kranz; 4,236,514 to Moretti; 4,452,240 also to Moretti; 4,508,115 to Warncke; 4,552,140 to Cowley; and 4,559,939 to Levine. The devices of Warncke, Kranz, Moretti '240, Cowley and Levine have their own supply of air or oxygen from containers mounted on the head enclosures or strapped to the body of the wearer. The hoods of both of the Moretti patents as well as the hoods of Kranz, Warncke, Cowley and Levine are also inflatable. The hood of Warncke deploys out of the rim of the helmet shown in the patent. The device of the Levine patent is for aircraft passengers.
There are also a number of patented prior art emergency devices which go beyond a mere protective enclosure for the head or face of a person in a hostile environment. Examples of such patents are U.S. Pat. Nos. 2,960,292 to Pitta; 3,768,467 to Jennings; 3,911,913 to June; 4,523,588 to Dolsky; and British Patent No. 2,086,731 to Edwards.